【目的】提高回旋加速器生产放射性18F核素的效率,降低正电子发射断层显像(PET)的用药成本。【方法】通过对回旋加速器的各种运行条件(包括束流强度、轰靶时间和靶压)、不同质地的生产原料的重复测定,对结果进行对比优选。【结果】回旋加速器生产日常常用核素18F的最佳条件为束流强度为40μA,轰靶时间为70min,富氧水丰度大于94%,富氧水用量为1.2g时平均产量最高(超过30GBq)。有效降低PET日常生产18F-FDG用药成本。【结论】通过有选择地控制回旋加速器的运行参数、用不同质量、质地的原料可以根据日常用药量的需要以最经济的方式生产出所需的放射性核素18F。

Objective To establish a rapid, effective performance method for in-target synthesis of 13N-NH3 and inclease the yeild. Methods By improving the beam current of cyclotron, target pressure,bombard time and comparing with different concentration of additive in water, the best conditions for synthesizing 13N-NH3 were obtained and the product was purified by anion exchange resin. Result The best yield of 13N-NH3 was 2. 294GBg when the beam current of cyclotron was 35 μA, the target pressure was 150 kPa,bombard time was 15 min and the concentration of alcohol was 10 mmol/L. Moreover,the anion exchange resin could purify the product effectivly. Conclusion The improving method is effective for increasing the synthesis yield of 13N-NH3 and shortening the synthesis time.

OBJECTIVE:To study the biodistribution of L-[S-methyl-(11)C]-methioine ((11)C-MET) and explore its clinical application in positron emission tomography (PET) for brain tumor detection.METHODS:Twenty-four Wistar rats and divided into 6 equal groups and injected with (11)C-MET through the tail vein and killed by decollation at 5, 10, 20, 30 and 40 min after injection, respectively. The liver, brain, blood, heart, lung, kidney, and spleen were harvested to measure the radioactivity and calculate the biodistribution of (11)C-MET. PET imaging with (11)C-MET was performed in 6 normal volunteers and 30 patients with pathologically confirmed brain gliomas.RESULTS AND CONCLUSION:(11)C-MET showed high blood uptake and a long retention in the tumor mass, therefore can be a valuable tracer for PET imaging of brain tumor and the hypophysis.

Kryptofix 2.2.2 in 18F-FDG preparation is analized by gas chromatography coupled with OV-101 capillary column,and nitrogen-selective detector(NPD) and FID.Its retention time is 2.4 min from the column,and detected at the levels as low as 0.50 mg/L;the average residual of 30 normal batchs are 1.10±0.15 mg/L(n=30).Direct measurement of Kryptofix 2.2.2 in routine 18F-FDG preparation is effective using Gas Chromatography with a high sensitivity(50 times better than TLC method) for the daily quality control of 18F-FDG.

The [11C]methyl iodide (11C-CH3I ) is a very important methylated precursor in 11C labeled PET tracer synthesis. In order to get higher and more stable radiosynthesis yield of 11C-CH3I, this research aims at optimizing the key steps over the radiosynthesis procedure. After the system temperature of the module was optimized, a higher synthesis yield of 11C-CH3I (90.2 ±2.5)% was got, and 100% success rate of the synthesis was obtained at the same time. The synthesis time was 11min,and the radiochemical purity of the precursor was over 98%. Thus optimization of the system can lead to producing 11C-CH3I with higher and more stable yield.

Objective To establish a rapid,effective method for the synthesis of 11C-acetate and study the biodistribution of 11C-acetate in mice in order to support the clinical demand in PET center.Methods By unloading the 11C-CO2 to the vessel which contained 0.2 ml CH3MgBr in THF,the first reaction could be going,then phosphoric acid(aqueous 17%v/v,0.2 ml)was added to the residue,and the produce was distilled at 170 ℃ into a vial containing 5 ml physiological phosphate buffer.The mice receiving 11C-acetate were sacrificed,the liver and tissue samples from other organs were weighed and radiocounted.Results Only 15 min was taken from 11C-CO2 to 11C-acetate and the yield was 34.6%.Chemical and radiochemical purity was more than 99% and 98%.The radioactivity was mainly distributed in liver and kidney.Conclusion The synthesis which has been improved the condition of reaction is rapid,effective and the yield is higher than before.

Objective To study the biodistribution of 11C-choline and understand the role of the brain tumor PET clinic imaging with the new radiotracer. Methods 24 Wistar rats, after being divided into 6 groups, were injected by the veins of tail with 11C-choline and then killed by decollation at the time of 5,10,20,30,40 and 60 minutes respectively. The liver, brain, blood, heart, lung, kidney, and spleen were selected to measure the radio counts and calculate biodistribution, and the 5 normal volunteers and 15 cases of brain gliomas proved by pathology were finished in the research. Conclusion 11C-choline had a high blood uptake and also have a long retention in the tumor mass; therefore it had proved to be a valuable brain tumor and hypophysis PET imaging tracer.

By using the11C-CO 2 as the primary material from the cyclotron, An active reagent group-11C methyliodine (11C-CH3 I)can be made. On-line 11C methylation using11C-CH3I has been us ed for fast preparation of L-methyl-11C methionine (11C-MET). T he novel approach can get11C-MET in 2min from11C-CH3I, the synthesis yield was 85%, the radiochemical purity was over 99%. This paper had also done some research about the quality control of this PETtracer .It was proved that t his method can be utilized for the fast preparation of11C-MET for PET cen ter.

正电子核素:碳-11广泛应用于氨基酸、脂肪酸、受体的配体和神经递质等分子标记,其标记的PET显像剂在生物医学和药理学研究中实现真正意义上的分子生物学显像.利用PET显像临床应用于探查肿瘤、脑血流、代谢、蛋白质合成和神经递质功能活动,在基础科学和临床研究中具有非常重要的意义。

笔者对75例鼻咽癌放疗后18F-脱氧葡萄糖（FDG）PET 显像结果进行回顾性分析,评价18F-FDG PET显像诊断原发性鼻咽癌放疗后病灶残留或复发的价值,现报道如下。一、资料与方法

11C-胆碱为近年来研发的一种新型肿瘤PET显像剂.本文就其在脑瘤、肺癌、食管癌、直肠癌、前列腺癌、软组织肿瘤和膀胱癌等的PET显像应用方面综述.

Objective To apply a new PET tracer: L-[methyl-~(11)C]methionine(~(11)C-MET) in preliminary clinical study.Methods ~(11)C-MET had been labeled by the automated module.The biodistribution was studied on rats.We assessed the usefulness of~(11)C-MET in brain tumor imaging for 4 patients. Results The biodistribution showed that most part of activity were in liver and intestine.and the radioactivity in brain cells and blood had a long relay time.Conclusions The clinical results showed that~(11)C-MET was suitable for PET brain tumor imaging.

Objective To study the on - line automatic synthesis of [N - methyl - 11C]choline and to apply it in preliminary clinical application. Methods 11C - Choline has been labeled on - line with column - method. The biodistribution was studied with Wistar mices. Results The radiochemistry purity was great than 99 % , the synthesis yield was 85 % . The biodistribution showed that most part of activity were in kidney, liver and intestine. Conclusions It is suitable for PET center to synthesize 11C - choline with column - method because the method has high yield, and operated easily.

目的 探讨氮 - 13-氨水 （ 13 N -NH3 ）脑血流灌注显像在早期缺血性脑梗死的诊断价值 .方法 对 5例缺血性脑梗死、10例对照组 （无脑血管病史的成年人 ） ,在首次CT检查后 1小时内静脉注射13 NH3 · 74 0～ 92 5MBq ,3分钟后 ,行T +E三维方式脑血流灌注显像 .图象分析采用视图分析及镜像比值法测量左 /右侧相应脑区SUV比值 （SU Vr） .结果 对照组左 /右脑区SUVr为 1.0± 0 .1.脑梗死组SUVr均 ＜0 .7（比值介于 0 .33～ 0 .6 9,平均 0 .5 1） . 5例缺血性脑梗死患者共发现病灶 12个 ,明显多于其他影像手段所检出病灶数 .结论 13 N -NH3 PET显像作为一种灵敏度高、定位准确且安全的功能影像学检查手段值得在临床中进行推广 ,对缺血性脑梗死的早期诊断具有重要临床价值 .

Objective To determine whether 18F-fluorodeoxyglucose (FDG) PET imaging can predict malignancy grade in lymphoma. Methods 32 patients (NHL, n=29 and HD, n=3) were divided into 3 groups according to pathological REAL standard as low-grade, middle-grade and high-grade malignancy, and all cases were examined by 18F-FDG whole body PET scan. Visual and semi-quantitative analysis were used, maximal standard uptake values (SUV max) of tumor lesion was calculated. Results In 32 malignant lymphoma patients, the group of low-grade malignancy lymphoma's SUV max: 2.95±1.72, the group of middle-grade malignancy lymphoma's SUV max: 8.72±5.68 and the group of high-grade malignancy lymphoma's SUV max: 10.30±4.05. Conclusion 18F-FDG PET imaging can predict malignancy grade in malignant lymphoma accurately.

Objective To study the diagnostic value of 18 F-fluorodeoxyglucose (FDG) imaging in primary nasopharyngeal carcin oma (PNC). Method s All fifty-one patients underwent 18 F-FDG PET imaging an d thirty-one of them with biopsy data. The diagnosis was based upon pathologic and clinical follow-up studies. Results Diagnostic sensitivity, specificity and accuracy of 18 F-FDG PET i maging in PNC was 96.00%, 76.92% and 86 27%,respectively, whereas the positive predictive value was 80.00% and the negative predictive value was 95.24 %. There was significant difference in mean SUV values among PNC, nasopharyngiti s and non-nasopharyngeal lesion groups. Conclusion The high sensit ivity and negative predictive value of 18 F-FDG PET imaging for d etection of PNC suggest that it has important value in clinical practice.

Objective To preliminarily study the blood perfusion and ammonia metabolism of pituitary using dynamic 13 N-NH_3 PET imaging. Methods 13 N-NH_3 PET imaging was performed on 21 subjects without pituitary diseases, 6 of them underwent dynamic PET imaging, and 8 of them underwent brain MRI in addition to PET. PET images were registered with MRI. Results The pituitary could be clearly seen in 13 N-NH_3 PET images, and being confirmed by PET/MRI image fusion. The size of pituitary was (1.07±0.17) cm×(1.09±0.15) cm×(1.14±0.17) cm, the standard uptake value (SUV) was 3.84±1.75, and the radioactivity ratio of pituitary to thalamus was 1.35±0.63. Pituitary image was seen at 10 s after the internal carotid was seen in dynamic 13 N-NH_3 PET imaging. 13 N-NH_3 was retained in pituitary, and was hardly cleaned out within 20 min. The radioactivity ratio of pituitary to internal carotid was 0.75±0.13 when the radioactivity of internal carotid was at its highest level. Conclusions The blood flow and ammonia metabolism of pituitary can be observed with dynamic 13 N-NH_3 PET imaging. Ammonia is highly extracted by pituitary, and metabolized in pituitary cells.

目的建立快速准确测定PET示踪剂13N-氨水中的细菌内毒素含量的方法.评估动态比浊法在半衰期短的PET临床用药中的实用价值. 方法通过制备5.0 Eu/ml、0.5 Eu/ml、0.05 Eu/ml的标准内毒素溶液进行测定,制出LogT-LogC 标准曲线图,根据样品的反应时间代入曲线方程得出13N-氨水中细菌内毒素的含量. 结果标准曲线在标准内毒素浓度范围为0.05Eu/ml～5.0Eu/ml时线性关系良好(γ=0.99969),精密度和样品阳性对照的回收率都比较满意.样品阳性对照的回收率一般为75%～120%,阳性样品回收率越接近100%,则表明此次检验的准确性越高.此方法最低检测范围为0.05Eu/ml. 结论与传统内毒素检测方法凝胶法相比,动态比浊法具有快速、准确、有效、定量地测定13N-氨水中的细菌内毒素含量的优势.

Objective To evaluate the feasibility of ~ 13N-ammonia PET in diagnosing ischemic cerebrovascular disorders. Methods A total of 25 subjects were investigated. Five healthy volunteers served as normal control. Twenty patients included 13 with transient ischemic attack(TIA), 6 with brain infarction and 1 with moyamoya disease. 740～925 MBq of ~ 13N-ammonia was injected intravenously. 3～5 min later, PET imaging was performed with T+E 2D acquisition with Siemens ECAT EXACT HR~+ PET scanner. Image analysis was done by visual and semiquantitative estimating. Standardized uptake value(SUV) was measured in mirror regions of cerebrum with autocopy methods. Nine patients underwent drug stress with oral acetazolamide (ACZ). Images were compared before and after oral ACZ intervention. Results Physiological brain uptake with SUV ratio of 0.99±0 15 (n=5, left/right) was observed in healthy volunteers. L/N0.85 was defined as hypoperfusion whereas L/N0.7 was infarct area(L/N represents the lesioned to normal in the symmetric area of cerebral cortex). Of the 20 patients, the positive rate in PET was 53.8%. Compared with other modalities, the positive rate with MRI and CT was 25.0% and 16.7%(P0.05). Twenty-nine hypoperfusion focuses were found in TIA cases, the average SUV was 1.78±0.41 which was much lower than that of normal controls (2.51±0.52,t=8.78,P0 05),13 infarct focuses were found in patients with brain infarction. The average SUV was 1.05±0.23 which was significantly lower than that of normal controls and TIA patients(t=5.9,P0.001). The number of identified focus was increased from 29 to 35 after oral ACZ stress, positive rate for lesion detection was increased by 17 1%; which enabled positive rate for cases to escalate from 53.8% to 62.5%. The SUV ratio in rest imaging was 0.87±0.11,the mean SUV was decreased to 0.77±0.07 in focuses after stress(t=6.47,P0.05). Conclusions The results show that PET with ~ 13N-ammonia as radioactive tracer was a safe and noninvasive, sensitive and accurate functional imaging modality for brain perfusion. The oral ACZ stress is a safe, simple and reliable diagnostic method for ischemic cerebrovascular disorders. It is of important uses in detecting the potential reserve of cerebral blood flow.